The invention relates to optics, and more particularly to selective optical means, especially those permitting the tuning of lasers.
Known selective optical devices are, for example, diffraction gratings and Fabry-Perot calibrators. Usually, it is necessary to use these with complementary devices which increase their bulk. In the field of lasers with variable tuning, the following selectors are often used:
diffraction grating of large dimensions plus mirror; PA1 diffraction grating (in Littrow arrangement) plus an optical transmission system such as that known as telescopic (enlargement of the diameter of the beam); PA1 combination of a diffraction grating and a Fabry-Perot calibrator; and PA1 combination of two Fabry-Perot calibrators.
The laser cavities thus obtained are quite large and are subject to numerous different modes, which can be disadvantageous in certain applications.